1. Field of the Invention
The present invention relates to an electronic volume device and a remote controller thereof, and in particular, to an electronic volume device remotely controlled based on a volume control signal defined by the Blue tooth standard specification and a remote controller thereof.
2. Description of the Related Art
A technology that remotely controls an electronic volume mounted in an audio player by operating a volume control key of a remote controller is disclosed in Japanese Patent Application Laid-Open No. 5-308230. The remote controller is provided with a “+(volume up)” key and a “−(volume down)” key as the volume control key and, in some cases, is further provided with a “mute” key for attenuating the volume to the lowest level at a stretch.
As the Blue tooth standard is defined a standard for remotely controlling the volume of a head set mounted on a head from an audio gateway, for example, a mobile phone, which is connected to the head set by radio. In this standard, 16 steps from “0” to “15” are prepared as a volume scale.
For example, in the volume control between a TV and its remote controller, an absolute volume is supplied to the TV by the remote controller, but a signal for relatively changing a present volume, for example, a signal of “volume up by one step” or a signal of “volume down by one step” is outputted to the TV from the remote controller. A player and a remote controller complying with the Blue tooth standard transmit an absolute volume of 16 steps between them to recognize a present volume and for example, when the present volume is “8”, if the “+” key of the remote controller is pressed down, the remote controller gives a direction of volume “9” to the player. When the volume is changed from “9” to “10” in the audio player, the change information is transmitted also to the remote controller. Thus, if the “+” key is next pressed down in the remote controller side, the remote controller gives a direction of volume “11” to the audio player.
It is desired in consideration of operating the electronic volume with gloves on that the electronic volume of the head set mounted on a helmet be reduced in the number of steps of volume control, thereby being simplified. For example, it is desirable that the volume scale be narrowed to four steps, for example, “mute”, “small volume for a halt”, “middle volume for running at low and middle speeds”, and “large volume for running at high speed”. However, when the number of steps of volume control of the player is reduced, the following drawbacks could be produced.
In FIG. 24, when the volume scale of a remote controller is reduced to 4 steps of from Dcom[1] to Dcom[4] in accordance with 4 steps of a player A, even if a player B having a volume scale of 10 steps is remotely controlled by this remote controller, the player B cannot output volume corresponding to Dvol2 [5] to Dvol2[10] and hence cannot sufficiently increase volume.
In a case where the volume level Dcom is discontinuously assigned to the remote controller, as shown in FIG. 25, in order to cope with such a technical problem, when the respective Dvol1s are assigned to the respective Dcoms in the same way like the player A, there is no problem, but when the Dvol2s are divided into 10 steps like the player B, some volumes cannot be set by the remote controller; then, when the respective Dvol3s do not agree with the respective Dcoms like a player C, it is impossible to remotely control the player C by the remote controller.
Further, as shown in FIG. 26, in a case where the remote controller has a volume scale of 16 steps, as long as the player A having the volume scale of 4 steps is given a direction of volume within a range of from Dcom[1] to Dcom[4] from the remote controller, the player A can control the electronic volume at the directed volume. However, when the “+” key is continuously pressed down beyond the Dcom [4] to increase the volume, for example, to Dcom [8], even if the “−” key is thereafter continuously pressed down so as to decrease the volume, the remote controller transmits Dcom[7], Dcom[6], and Dcom[5] to the player A but the player A can not decrease the volume in this range. That is, there is a problem that although the “−” key is continuously pressed down, the volume is not decreased.
In case where a player has a volume scale of 4 steps but the steps are discrete like the player B, there is a problem that even if the remote controller supplies the player with Dcom[5] and then the “+” key is further pressed down, the volume is not increased until the volume reaches Dcom[10]. Even if the number of steps of the volume scale is increased like the player C, such a problem will similarly occur.
As described above, there is presented a technical problem that when the volume scale of the player is decreased to a smaller number of steps than the 16 steps of the Blue tooth standard specification, ease of operation by the remote controller is impaired.
In this regard, such a technical problem can be solved by separately preparing a remote controller specifically designed for the number of steps of volume control of the player, but the general versatility of the remote controller is impaired to interfere with a combination of the remote controller and the other devices, which does not square with the concept of the Blue tooth that places emphasis on general versatility.